Wireless Local Area Network (lan) Receiver Rf Front-end Circuit Research And Design

The development of wireless local area network (WLAN) has been growing rapidly. It is widely used not only among the portable electronic products, but also in fixed electronic products such as flat-screen television and digital picture frame. Low power multiple protocols in single chip WLAN transceiver design is a hot topic in industry.This thesis analyzes and designs a receiver radio-frequency (RF) front-end which is applied for WLAN IEEE802.11a/b/g. It consists of low noise amplifier (LNA) and mixer. The thesis has designed the receiver system firstly. This receiver adopts direct-conversion zero-IF structure. According to the requirement of IEEE802.11a/b/g protocol on sensitivity, the maximum input signal, the channel bandwidth and bit error rate (BER), all of the receiver specification parameters are defined. These parameters are distributed to each circuit block. Then low noise amplifier and mixer are analyzed and designed. To save off-chip input balun, a single input differential output LNA is designed. Capacitor cross-coupling technique is adopted to improve LNA’s noise performance. A switch-control five-port inductor is proposed as LNA’s load to achieve single-inductor dual-band (SIDB) application (2.4GHz/5GHZ), which can reuse the whole front-end circuits and save die area. A high linearity low1/f noise current-mode passive mixer with variable resistor load is proposed to increase the dynamic range of the RF front-end.The first version of RF front-end for IEEE802.11a protocol is implemented with SMIC0.13/μm CMOS process. It works at1.2V power supply and the power consumption is34.1mW, Test result shows that its double side band (DSB) noise figure is7.2dB and input third inter-modulation point (IIP3) is-16.8dBm with high gain of35dB. The IIP3is5.2dBm with low gain of13dB. Compared with high gain mode the power consumption at low gain mode can decrease8.3mW.The second version of SIDB (2.4GHz/5GHz) RF front-end which is used for IEEE802.1la/b/g protocol is realized with TSMC65nm CMOS process. It works at1.2V power supply and the power consumption is33.6mW. Test result shows that its DSB noise figure is5.4dB and IIP3is-16dBm with high gain of37.7dB at2.4GHz. In addition, its DSB noise figure is8.4dB and IIP3is-14dBm with high gain of33.7dB at4.5GHz. The resonance frequency deviates750MHz from5.25GHz which is defined by the protocol.